Battery cell, battery pack, energy storage system and power utilization device

Abstract

The utility model discloses a battery monomer, battery pack, energy storage system and power utilization device, the battery monomer includes roll core and shell, the roll core includes: the core body, cushion and shell, the core body is wound around a winding center, the winding center is provided with the central hole, the cushion is arranged in the central hole, the shell defines the accommodation space, the shell is provided with the battery pack, the battery pack is arranged in the accommodation space, and the battery pack is arranged in the accommodation space. The core body and the buffer cushion are both arranged in the containing space, and at least one of the two ends, in the winding axial direction, of the buffer cushion protrudes out of the end, in the winding axial direction, of the core body. Therefore, on one hand, stress can be balanced, inner ring corner gaps can be reduced, lithium precipitation can be improved, the lithium precipitation probability of the roll core can be reduced, the cycle life and reliability of the roll core can be improved, the curvature of the inner ring can be improved, the inner short probability can be reduced, potential safety hazards can be reduced, and more importantly, the infiltration path can be shortened, the infiltration speed can be increased, and the infiltration efficiency can be improved; in the circulation process, the electrolyte can flow back in time, and polarization is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a battery cell, a battery pack, an energy storage system and an electrical device. Background Art

[0002] In the related art, the diaphragm and the anode and cathode plates on both sides of the diaphragm form a winding body (core body), and the winding body is wound around a winding center to form a winding core, and the winding core is assembled into a shell.

[0003] However, the core has few wetting paths and can only be wetted through the openings on both sides of the core. The wetting path is long and the wetting efficiency is low, which leads to untimely electrolyte reflux and increased polarization during the cycle. At the same time, the corner gap of the curved part of the core is large, which easily causes lithium deposition, reducing the cycle life of the core. The inner ring of the core is prone to brittle fracture, and there is a risk of internal short circuit, posing a safety hazard. Utility Model Content

[0004] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the utility model is to provide a battery cell with higher working reliability, lower safety hazards, longer cycle life, high infiltration efficiency, and reduced polarization.

[0005] The utility model also provides a battery pack using the battery monomer.

[0006] The utility model further proposes an energy storage system having the above battery pack.

[0007] The utility model also provides an electric device adopting the energy storage system.

[0008] In the first aspect, an embodiment of the utility model provides a winding core, comprising: a winding core and a shell, wherein the winding core is arranged in the shell, and the winding core comprises: a core body, a buffer pad and an outer shell, the core body is wound around a winding center, and the winding center has a center hole, the buffer pad is arranged in the center hole, the outer shell defines an accommodating space, and the core body and the buffer pad are both arranged in the accommodating space.

[0009] According to the winding core of the embodiment of the utility model, by setting a buffer pad, on the one hand, the force can be balanced, the inner circle corner gap can be reduced, and lithium deposition can be improved to reduce the probability of lithium deposition in the winding core, thereby improving the cycle life and reliability of the winding core, and the inner circle curvature can be increased to reduce the probability of brittle fracture of the inner circle pole piece to reduce the probability of internal short and reduce safety hazards. More importantly, the wetting path can be shortened and the wetting speed can be increased to improve the wetting efficiency. During the circulation process, the electrolyte can flow back in time to reduce polarization.

[0010] According to some embodiments of the present invention, at least one of the two ends of the buffer pad in the winding axis direction protrudes out of the end of the core body in the winding axis direction.

[0011] In the above technical solution, at least one end of the buffer pad extending into the electrolyte is protruding from the end on the same side of the core body, so that the electrolyte cannot enter the gap in the inner circle of the core, so that the electrolyte level can be increased. A higher electrolyte level can speed up the wetting speed and make the electrolyte level closer to the other end of the core body on the winding axis, thereby shortening the wetting path and improving the wetting efficiency.

[0012] According to some embodiments of the utility model, the core body includes: a diaphragm and a first pole piece and a second pole piece located on both sides of the diaphragm in a winding radial direction, the buffer pad protrudes from the first pole piece and the second pole piece, and the winding radial direction is orthogonal to the winding axial direction.

[0013] In the above technical solution, the buffer pad protruding from the core body can make the buffer pad contact with the electrolyte first, break the surface tension of the electrolyte, and further improve the wetting efficiency and wetting effect.

[0014] In some embodiments, the shell includes: an insulating sheet located on the side of the core and a bottom guard plate located at one end of the core, and an end of the buffer pad is closer to the bottom guard plate than the end of the core.

[0015] In the above technical solution, the end of the buffer pad is protruded from the end of the core body and is arranged relatively to the adjacent bottom guard plate, so that the electrolyte accumulated at the bottom of the shell and the outer shell under the action of gravity can be guided by the buffer pad to infiltrate upward, further improving the infiltration efficiency and reducing the infiltration path.

[0016] In some embodiments, the bottom guard plate is integrally formed with the buffer pad.

[0017] In the above technical solution, the bottom guard plate and the buffer pad can be processed as one piece, which improves the processing efficiency and makes the assembly between the core body and the buffer pad easier and more efficient.

[0018] In some embodiments, the bottom guard plate is sealed to the insulating sheet so that the bottom of the accommodating space is separated from the outside.

[0019] In the above technical solution, the utility model arranges a buffer pad on the inner circle of the core to increase the thickness of the core, and the core is arranged in the shell of the battery cell. The thickness of the core is greater, and the gap between the shell and the core is smaller. At the same time, the accommodating space is constructed as a sealed space, so that the electrolyte in the outer shell will not overflow into the shell, the gap that the electrolyte can fill is smaller, and the liquid level of the electrolyte can be higher, so as to further shorten the infiltration path and improve the infiltration efficiency.

[0020] According to some embodiments of the present invention, the buffer pad includes: a main body and a protective layer, wherein the protective layer covers the main body to isolate the electrolyte.

[0021] In the above technical scheme, the material of the main body can be a mixture of one or more materials such as polyurethane, silicone, rubber, etc., which plays a buffering role to shrink or expand to absorb the force on the core, effectively perform mechanical balance and protection on the core, and the protective layer can be a mixture of one or more materials such as polyethylene, polypropylene, polyvinyl chloride, etc., which can form a dense protective layer to prevent the electrolyte from entering the buffer pad and corroding the buffer pad, thereby improving the reliability and stability of the buffer pad and improving the reliability and stability of the core.

[0022] In some embodiments, a dimension of the main body portion in the winding radial direction is 0.5 mm to 3 mm.

[0023] In the above technical solution, the thickness of the main body is made more reasonable, so that the space occupied by the buffer pad can be taken into account while having a stable and reliable protective effect, so as to take into account the energy density of the core.

[0024] In some embodiments, the protective layer has a size of 10 um to 50 um in the winding radial direction.

[0025] In the above technical solution, the thickness of the protective layer is made more reasonable, and a dense protective film can be formed. At the same time, the thickness is more reasonable, which can reduce material costs and take into account space occupancy.

[0026] In some embodiments, the cushion further comprises a connecting layer, wherein the connecting layer is coated on the protective layer and is suitable for connecting with the core.

[0027] In the above technical solution, the connecting layer can be constructed as an adhesive layer, and a PVDF coating can be coated on the outside of the protective layer to make the hot pressing between the core and the buffer pad simpler and more convenient, improve the structural stability and reliability of the core, and make the core structure less likely to loosen.

[0028] In some embodiments, there is at least one winding core, a liquid injection portion is formed on the outer shell, and the outer shell is not connected to the shell.

[0029] In the above technical solution, the use scenarios of the winding core can be enriched, making the battery cells of the embodiment of the utility model more diverse.

[0030] In a second aspect, an embodiment of the utility model provides a battery pack, including: the battery cell described in the above embodiment.

[0031] In a third aspect, an embodiment of the utility model provides an energy storage system, including: the battery pack described in the above embodiment.

[0032] In a fourth aspect, an embodiment of the utility model provides an electrical device, comprising: the battery pack described in the above embodiment.

[0033] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0035] Figure 1 is a schematic diagram of an electrical device according to an embodiment of the utility model;

[0036] Figure 2 is a schematic diagram of a battery pack according to an embodiment of the utility model;

[0037] Figure 3 It is a schematic diagram of the electrolyte liquid level in the prior art;

[0038] Figure 4 It is a schematic diagram of the electrolyte infiltration path in the prior art;

[0039] Figure 5 is a schematic diagram of the electrolyte level according to an embodiment of the utility model;

[0040] Figure 6 is a schematic diagram of the electrolyte infiltration path according to an embodiment of the utility model;

[0041] Figure 7 is a schematic diagram of a winding core according to an embodiment of the utility model;

[0042] Figure 8 It is a schematic diagram of the cooperation between the buffer pad and the bottom guard plate according to an embodiment of the utility model;

[0043] Fig. 9 is a schematic diagram of a battery cell according to an embodiment of the utility model;

[0044] Fig.10 is a partial cross-sectional schematic diagram of a battery cell according to an embodiment of the utility model;

[0045] Fig.11 It is a schematic diagram of a buffer pad according to an embodiment of the utility model.

[0046] Reference numerals:

[0047] Core 100,

[0048] Core 10, anode pole piece 11, cathode pole piece 12, diaphragm 13,

[0049] The core inner ring 101, the core outer ring 102, the core middle ring 103,

[0050] Buffer pad 20, main body 21, protective layer 22, connecting layer 23,

[0051] Shell 30, insulation sheet 31, bottom guard plate 32,

[0052] Battery cell 200, housing 210,

[0053] Battery pack 300, power device 400, controller 500, motor 600, box 700,

[0054] Winding center a, accommodating space b. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0056] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those generally understood by technicians in the technical field of the present invention; the terms used in the present invention and in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of the present invention or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0057] The reference to "embodiment" in the present invention means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0058] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection", "connection", and "attachment" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] The term "and / or" in the present invention is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects before and after are in an "or" relationship.

[0060] In the embodiments of the present invention, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present invention shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary and should not constitute any limitation on the present invention.

[0061] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0062] In the description of the present invention, a first feature being “above” or “below” a second feature may include that the first and second features are directly in contact with each other, or may include that the first and second features are not in direct contact but are in contact with each other via another feature therebetween.

[0063] In the description of the present invention, a first feature “above”, “over” and “above” a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0064] The term "plurality" used in the present invention refers to more than two (including two).

[0065] In the embodiment of the utility model, the winding core 100 is anode electrode sheet 11, cathode electrode sheet 12 and diaphragm 13 rolled together by the winding needle mechanism of the winding machine. Adjacent cathode electrode sheets 12 and anode electrode sheets 11 are separated by diaphragm 13 to prevent short circuit. The winding needle mechanism defines a winding center a. The winding needle can be needle-shaped, so that the core body 10 can be wound around an axis defined by the needle-shaped winding needle as the winding center a to form a cylindrical winding core, which can be processed into a cylindrical battery cell. The winding needle can also be plate-shaped, and the core body 10 can also be wound around a plane defined by the plate-shaped winding needle to form a square winding core, which can be processed into a square battery cell. In the embodiment where the corresponding winding needle is needle-shaped, the winding center is an axis, and a cylindrical center hole is formed at the winding center. In the embodiment where the winding needle is plate-shaped, the winding center is a plane, and a plate-shaped center hole is formed at the winding center.

[0066] In the embodiment of the present invention, the battery cell 200 may be a secondary battery. A secondary battery refers to a battery cell 200 that can be continuously used by activating active materials by charging after the battery cell 200 is discharged.

[0067] The battery cell 200 can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, etc., which is not limited in the embodiments of the present invention.

[0068] The battery pack 300 mentioned in the embodiment of the present invention refers to a single physical module including one or more battery cells 200 to provide higher voltage and capacity. When there are multiple battery cells 200, the multiple battery cells 200 are connected in series, in parallel or in mixed connection through a busbar.

[0069] In some embodiments, a plurality of battery cells 200 may be combined into a battery module, that is, when there are a plurality of battery cells 200 , the plurality of battery cells 200 are arranged and fixed to form a battery module.

[0070] In some embodiments, the battery pack 300 includes a case 700 and battery cells 200, at least one battery cell 200 or at least one battery module is accommodated in the case 700, and the case 700 has an accommodating space, and at least one battery cell 200 or at least one battery module is accommodated in the accommodating space.

[0071] In some embodiments, the box 700 can be used as a part of the chassis structure of the vehicle. For example, part of the box 700 can become at least a part of the floor of the vehicle, or part of the box 700 can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0072] In some embodiments, the battery pack 300 or the battery module may be part of an energy storage system, which may be an energy storage container, an energy storage cabinet, etc., in which batteries and energy shut-off modules are integrated.

[0073] The development of battery technology must take into account many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, the safety performance of the battery must also be considered.

[0074] It is understandable that since the energy people need is highly temporal and spatial, in order to rationally use energy and improve energy utilization, it is necessary to use a medium or device to store one form of energy in the same form or convert it into another form of energy, and then release it in a specific form of energy based on future application needs. As we all know, to achieve the goal of carbon neutrality, green energy is currently mainly used to replace fossil energy to achieve the purpose of generating green electricity.

[0075] The current green energy mainly includes solar energy, wind energy, hydropower, etc. However, solar energy and wind energy generally have problems of strong intermittency and large volatility, which will cause unstable voltage of the green power grid (not enough electricity during peak hours and too much electricity during low hours). Unstable voltage will cause damage to electricity. Therefore, it may cause the problem of "wind and solar power abandonment" due to insufficient electricity demand or insufficient grid acceptance capacity.

[0076] To solve the problem of insufficient electricity demand or insufficient grid acceptance capacity, we must rely on energy storage systems, etc. That is, the energy storage system converts electrical energy into other forms of energy through physical or chemical means and stores it, and then converts the energy stored in the energy storage system into electrical energy when needed. In simple terms, the energy storage system is similar to a large "power bank", which stores electrical energy when there is sufficient light energy and wind energy, and releases the stored electrical energy when needed.

[0077] At present, energy storage (i.e. energy storage) has a wide range of application scenarios, including power generation side energy storage, grid side energy storage, renewable energy grid-connected energy storage and user side energy storage. The corresponding types of energy storage systems include:

[0078] (1) Large energy storage containers used in grid-side energy storage scenarios can serve as high-quality active and reactive power regulation power sources in the grid, achieve load matching of electric energy in time and space, enhance the ability to absorb renewable energy, and are of great significance in grid system backup, relieving peak load power supply pressure, and peak and frequency regulation;

[0079] (2) The main operating mode of small and medium-sized energy storage cabinets used in industrial and commercial energy storage scenarios (banks, shopping malls, etc.) on the user side and small household energy storage boxes used in home energy storage scenarios on the user side is "peak shaving and valley filling". Since there is a large price difference in electricity charges at peak and valley locations according to electricity demand, after users have energy storage equipment, in order to reduce costs, they usually charge the energy storage cabinets / boxes during the low electricity price period; during the peak electricity price period, the electricity in the energy storage equipment is discharged for use to achieve the purpose of saving electricity bills. In addition, in remote areas and areas prone to natural disasters such as earthquakes and hurricanes, the existence of household energy storage systems is equivalent to users providing themselves and the power grid with backup power, eliminating the inconvenience caused by frequent power outages due to disasters or other reasons.

[0080] In combination with the above-mentioned situation of storing energy by physical or electrochemical means, taking electrochemical energy storage as an example, the energy storage system may include at least one of the above-mentioned batteries, using the chemical elements in the battery as energy storage media, so as to realize the charging and discharging process through the chemical reaction or change of the energy storage medium. In simple terms, the electric energy generated by light energy and wind energy is stored in at least one battery through the chemical reaction or change of the energy storage medium, and when the use of external electric energy reaches a peak, the electric energy stored in at least one battery is released for use through the chemical reaction or change of the energy storage medium, or transferred to a place where the electric energy is scarce for use.

[0081] In summary, the battery cell 200 serves as the smallest energy unit of the battery module, battery pack 300, and energy storage system, and a battery cell 200 has one or more cores 100, which are arranged in the shell 210. When assembling the battery cell 200, the core 100 needs to be injected with electrolyte, and the core 100 is only opened on both sides for infiltration, and the infiltration efficiency is low, resulting in untimely electrolyte reflux and increased polarization during the cycle. At the same time, the corner gap of the curved part of the core 100 is too large, which is also prone to intermediate lithium deposition, reducing the cycle life of the core 100, and the inner ring 101 of the core is prone to brittle fracture, which poses a risk of internal short circuit and a safety hazard.

[0082] In other words, the core 10 is wound around the winding center a. Taking the case where the core 10 is wound twice, the part of the core 100 adjacent to the winding center a can be defined as the core inner circle 101, and the part away from the winding center a can be defined as the core outer circle 102. If it is wound more than two times, the innermost circle is defined as the core inner circle 101, and the outermost circle is positioned as the core outer circle 102. The winding center a is the axis or plane. Therefore, a part of the core 100 will bend during the winding process, and the distance between the anode electrode piece 11 and the cathode electrode piece 12 of the core inner circle 101 adjacent to the winding center a in the bent part is greater than the distance between the anode electrode piece 11 and the cathode electrode piece 12 of the core outer circle 102 away from the winding center a in the bent part, resulting in lithium deposition at the corner part of the core inner circle 101. The curvature of the core inner circle 101 is too small, resulting in brittle fracture of the core inner circle 101, which in turn causes internal short circuit, posing a safety hazard. In addition, the wetting path is long and the wetting efficiency is low, resulting in increased polarization.

[0083] In view of this, an embodiment of the utility model provides a battery cell 200, on which a buffer pad 20 is arranged on the winding center a, and the core 100 is wound around the buffer pad 20, which can not only balance the expansion force generated by the core 100 during the charging and discharging process, but also support the core inner ring 101 through the buffer pad 20, reduce the corner gap of the core inner ring 101, so as to improve the intermediate lithium deposition and enhance the cycle life and reliability of the core 100, and at the same time increase the curvature of the core inner ring 101 to prevent the brittle fracture of the pole piece of the core inner ring 101, reduce the probability of internal short circuit, reduce safety hazards, improve working stability, and increase the electrolyte liquid level and reduce the length of the infiltration path to improve the infiltration efficiency and avoid increased polarization.

[0084] The technical solution described in the embodiment of the present utility model is applicable to the battery pack 300 and the electric device 400 using the battery pack 300 .

[0085] The power-consuming device 400 may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle may be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, etc.; the electric toy includes a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer, etc. The embodiment of the utility model does not impose any special restrictions on the above-mentioned power-consuming device 400.

[0086] For the convenience of description, the following embodiments are described by taking the electric device 400 as a vehicle as an example.

[0087] Please refer to the figure, Figure 1 The schematic diagram of the structure of the vehicle provided by some embodiments of the utility model. The interior of the vehicle is provided with a battery pack 300, and the battery pack 300 can be arranged at the bottom, head or tail of the vehicle. The battery pack 300 can be used for power supply of the vehicle, for example, the battery pack 300 can be used as the operating power supply of the vehicle.

[0088] The vehicle may further include a controller 500 and a motor 600 . The controller 500 is used to control the battery pack 300 to supply power to the motor 600 . The motor 600 serves as a load, for example, to meet the power requirements for starting, navigating and driving the vehicle.

[0089] In some embodiments of the present invention, the battery pack 300 can be used not only as an operating power source for the vehicle, but also as a driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0090] Please refer to the figure, Figure 2 The exploded view of the battery pack 300 provided in some embodiments of the present invention. The battery pack 300 includes a battery cell 200 and a box 700 , and the box 700 is used to accommodate the battery cell 200 .

[0091] Among them, the box body 700 is a component for accommodating the battery cell 200, and the box body 700 provides a placement space for the battery cell 200. The box body 700 can adopt a variety of structures. In some embodiments, the box body 700 may include a tray and a box body 700, and the tray and the box body 700 cover each other to define a placement space for accommodating the battery cell 200. The tray and the box body 700 can be in various shapes, such as a cuboid, a cylinder, etc. The tray can be a hollow structure with one side open, and the box body 700 can also be a hollow structure with one side open. The open side of the box body 700 covers the open side of the tray, so as to form a box body 700 with a placement space. It can also be that the tray is a hollow structure with one side open, the box body 700 is a plate-like structure, and the box body 700 covers the open side of the tray, so as to form a box body 700 with a placement space. As an example, the battery cell 200 can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes, and the utility model has no special restrictions.

[0092] In the battery pack 300, there can be one or more battery cells 200. If there are more than one battery cell 200, the multiple battery cells 200 can be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 200 are both connected in series and in parallel. Multiple battery cells 200 can be connected in series, in parallel, or in mixed connection to form a battery module, and then the multiple battery modules are connected in series, in parallel, or in mixed connection to form a whole, and accommodated in the box 700. Alternatively, all battery cells 200 can be directly connected in series, in parallel, or in mixed connection, and then the whole formed by all battery cells 200 is accommodated in the box 700.

[0093] Reference below Figure 1-Figure 11 A battery cell 200 , a battery pack 300 , an energy storage system, and an electric device according to an embodiment of the present invention are described.

[0094] like Figure 6 and Figure 7 As shown, a battery cell according to an embodiment of the present invention includes a winding core 100 and a shell 210 .

[0095] Among them, the winding core 100 includes: a core body 10, a buffer pad 20 and an outer shell 30. The core body 10 is wound around a winding center a, and has a center hole at the winding center. The buffer pad 20 is arranged in the center hole. The outer shell 30 defines an accommodating space b. The core body 10 and the buffer pad 20 are both arranged in the accommodating space b.

[0096] Specifically, the buffer pad 20 can be roughly cylindrical or flat, and the buffer pad 20 is set on the winding center a, and the core body 10 can be set around the buffer pad 20, such as around two or more circles, the innermost circle that fits the buffer pad 20 is the core inner circle 101, and the outermost circle away from the buffer pad 20 is the core outer circle 102, and the multiple circles between the core inner circle 101 and the core outer circle 102 can be defined as the core middle circle 103.

[0097] It should be pointed out that the winding center a is defined by the winding needle. After the winding needle is withdrawn, a center hole is formed at the winding center a. A buffer pad 20 is arranged on the center hole, and the core body 10 is elastically supported by the buffer pad 20. This can prevent the inner circle pole piece (the pole piece part in the area where the inner circle 101 of the core is located) from brittle fracture after the core 100 is hot-pressed, and can improve the inner circle corner gap, balance the expansion force generated by the core 100 during the charge and discharge process, improve lithium plating, especially reduce the inner circle corner gap, improve lithium plating of the inner circle pole piece, reduce the risk of lithium plating caused by excessive inner circle corner gap, so as to improve cycle life and reliability.

[0098] In other words, the buffer pad 20 is set on the inner ring 101 of the core, which can increase the curvature of the inner ring to prevent the brittle fracture of the inner ring pole piece, avoid the risk of internal short caused by the brittle fracture of the inner ring, and reduce safety hazards. The setting of the buffer pad 20 can also make the inner ring pole pieces (the inner ring anode pole piece 11 and the inner ring cathode pole piece 12) more compact and reduce the inner ring corner gap.

[0099] Understandably, see Figure 3 and Figure 5 As shown, in the prior art, the electrolyte is injected into the housing 30 of the battery cell 200, and the electrolyte is located in the gap between the housing 210 and the winding core 100 and in the internal gap of the winding core 100 itself. The liquid level is H2, and the infiltration path is Figure 5 The arrows point to two infiltration paths on the outside of the core 10 and one infiltration path on the inside of the core 10, see Figure 4 and Figure 6 As shown, in the embodiment of the utility model, by arranging the buffer pad 20 on the inner ring 101 of the core, the internal gap of the winding core 100 itself can be reduced, and a part of the gap between the shell 210 and the winding core 100 is occupied, so that the gap for accommodating the electrolyte is smaller, and the liquid level height is H1, H1>H2. Compared with the prior art, the liquid level height of the utility model is significantly increased, so that the electrolyte can be infiltrated faster, and at the same time, Figure 6 As shown, the infiltration path of the utility model is as follows Figure 6 The arrow points to a shorter infiltration path, which can improve the infiltration efficiency.

[0100] According to the winding core 100 of the embodiment of the utility model, by providing the buffer pad 20, on the one hand, the force can be balanced, the inner circle corner gap can be reduced, and lithium deposition can be improved, so as to reduce the probability of lithium deposition in the winding core 100, and improve the cycle life and reliability of the winding core 100, and the inner circle curvature can be increased, and the probability of brittle fracture of the inner circle pole piece can be reduced, so as to reduce the probability of internal short and reduce safety hazards. More importantly, the infiltration path can be shortened, the infiltration speed can be increased, so as to improve the infiltration efficiency. During the circulation process, the electrolyte can flow back in time to reduce polarization.

[0101] In some embodiments, at least one of the two ends of the buffer pad 20 in the winding axial direction is disposed protruding from the end of the core 10 in the winding axial direction.

[0102] Specifically, the core 10 has two opposite ends in the winding axial direction, and at least one end of the buffer pad 20 in the winding axial direction is disposed adjacent to the inner wall surface of the shell 30 compared to the end of the core 10 on the same side in the winding axial direction.

[0103] That is to say, the utility model arranges at least one end of the buffer pad 20 that extends into the electrolyte to protrude from the end on the same side of the core 10, so that the electrolyte cannot enter the gap in the inner ring 101 of the core, so that the electrolyte level can be increased. A higher electrolyte level can speed up the wetting speed and make the electrolyte level closer to the other end of the core 10 on the winding axis, thereby shortening the wetting path and improving the wetting efficiency.

[0104] Exemplarily, the winding axis is the height direction, and at least the bottom end of the buffer pad 20 protrudes from the bottom end of the core body 10 .

[0105] like Figure 7 As shown, according to some embodiments of the utility model, the core 10 includes: a diaphragm 13 and a first pole piece and a second pole piece located on both sides of the diaphragm 13 in a winding radial direction, a buffer pad 20 protrudes from the first pole piece and the second pole piece, and the winding radial direction is orthogonal to the winding axial direction.

[0106] Specifically, taking the winding axis as the height direction as an example, the winding radial direction can be any direction in the horizontal plane, such as the length direction, the width direction, etc. The winding radial direction is orthogonal to the winding axis direction. When the core 10 is sectioned along the height direction, the core 10 includes a diaphragm 13 and a first pole piece and a second pole piece opposite to each other on both sides of the winding radial direction of the diaphragm 13. One of the first pole piece and the second pole piece is the anode pole piece 11, and the other is the cathode pole piece 12. The height dimension of the cathode pole piece 12 is greater than the height dimension of the anode pole piece 11, but the bottom ends of the cathode pole piece 12 and the anode pole piece 11 are both located above the bottom end of the buffer pad 20.

[0107] Therefore, by protruding the buffer pad 20 of the core body 10, the buffer pad 20 can be preferentially contacted with the electrolyte, breaking the surface tension of the electrolyte, so as to further improve the wetting efficiency and the wetting effect.

[0108] like Figure 5 , Figure 6 and Figure 7 As shown, in some embodiments, the shell 30 includes: an insulating sheet 31 located on the side of the core 10 and a bottom guard plate 32 located at one end of the core 10 , and the end of the buffer pad 20 is closer to the bottom guard plate 32 than the end of the core 10 .

[0109] Specifically, the insulating sheet 31 and the bottom guard plate 32 define the outer shell 30, and the insulating sheet 31 is arranged around the core body 10 on the circumferential side of the core body 10, such as: if the core body 10 is cylindrical, the insulating sheet 31 is sleeve-shaped, and if the core body 10 is rectangular, the insulating sheet 31 is composed of four plates assembled together, so as to separate the core body 10 from the shell 210 of the battery cell 200 on the circumferential side of the core body 10, and the bottom guard plate 32 is located at the bottom end of the core body 10, and is used to separate the bottom end of the core body 10 from the bottom wall of the shell 210 to achieve insulation protection for the core body 10, so that the end of the buffer pad 20 protrudes from the end of the core body 10 and is arranged relatively adjacent to the bottom guard plate 32, so that the electrolyte accumulated in the shell 210 and the bottom of the outer shell 30 under the action of gravity can be guided by the buffer pad 20 to infiltrate upward, thereby further improving the infiltration efficiency and reducing the infiltration path.

[0110] like Figure 8 As shown, in some embodiments, the bottom guard plate 32 is integrally formed with the cushion 20 .

[0111] Thus, the bottom guard plate 32 and the buffer pad 20 can be processed as one piece, which improves the processing efficiency and makes the assembly between the core body 10 and the buffer pad 20 easier and more efficient.

[0112] Of course, the structure of the bottom guard plate 32 and the buffer pad 20 of the embodiment of the utility model is not limited thereto. In other embodiments, the buffer pad 20 and the bottom guard plate 32 may be separately provided, and the bottom end of the buffer pad 20 may be in contact with the bottom guard plate 32, or may be spaced apart.

[0113] Combination Figure 3 and Figure 4 As shown, further, the bottom guard plate 32 is sealed and connected to the insulating sheet 31 so that the bottom of the accommodating space b is separated from the outside.

[0114] That is to say, the utility model sets a buffer pad 20 on the inner circle 101 of the core, which can increase the thickness of the core 10. The core 10 is set in the shell 210 of the battery cell 200. The thickness of the core 10 is larger, and the gap between the shell 210 and the core 10 is smaller. At the same time, the accommodating space b is constructed as a sealed space, so that the electrolyte in the outer shell 30 will not overflow into the shell 210, the gap that the electrolyte can fill is smaller, and the liquid level of the electrolyte can be higher, so as to further shorten the infiltration path and improve the infiltration efficiency.

[0115] In other words, the setting of the buffer pad 20 makes the gap between the shell 210 and the winding core 100 and the winding gap on the inner circle 101 of the core smaller, so that the gap for accommodating the electrolyte is smaller and the liquid level height after the electrolyte is injected is correspondingly higher.

[0116] It should be pointed out that the insulating sheet 31 and the bottom guard plate 32 can be sealed and connected by gluing, hot melting or the like, so that there is no gap between the bottom guard plate 32 and the insulating sheet 31 .

[0117] like Fig.11 As shown, according to some embodiments of the present invention, the buffer pad 20 includes: a main body 21 and a protective layer 22, and the protective layer 22 covers the main body 21 to isolate the electrolyte.

[0118] Specifically, the material of the main body 21 can be a mixture of one or more materials such as polyurethane, silicone, rubber, etc., which has a buffering effect so as to shrink or expand to absorb the force on the core 100, and effectively perform mechanical balance and protection on the core 100. The protective layer 22 can be a mixture of one or more materials such as polyethylene, polypropylene, polyvinyl chloride, etc., and can form a dense protective layer to prevent the electrolyte from entering the buffer pad 20 and corroding the buffer pad 20, thereby improving the reliability and stability of the buffer pad 20 and improving the reliability and stability of the core 100.

[0119] In some embodiments, the dimension of the body portion 21 in the winding radial direction is 0.5 mm to 3 mm.

[0120] Exemplarily, the size of the main body 21 can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc., that is, any value within the range including the endpoint values, so that the thickness size of the main body 21 is more reasonable, while having a stable and reliable protective effect, it can also take into account the space occupied by the buffer pad 20, so as to take into account the energy density of the core 100.

[0121] In some embodiments, the size of the protective layer 22 in the winding radial direction is 10 um to 50 um.

[0122] Exemplarily, the size of the protective layer 22 can be 10um, 20um, 30um, 40um, 50um, etc., that is, any value within the range including the endpoint values, so that the thickness of the protective layer 22 is more reasonable, and a dense protective film can be formed while the thickness is more reasonable, which can reduce material costs and take into account space occupancy.

[0123] like Fig.11 As shown, further, the buffer pad 20 also includes a connecting layer 23 , which is coated on the protective layer 22 and is suitable for connecting with the core 10 .

[0124] Specifically, the connecting layer 23 can be constructed as an adhesive layer, and a PVDF coating can be coated on the outside of the protective layer 22 to make the hot pressing between the core 100 and the buffer pad 20 simpler and more convenient, improve the structural stability and reliability of the core 100, and make the structure of the core 100 less likely to loosen.

[0125] like Fig. 9 and Fig.10 As shown, there is at least one winding core 100 , a liquid injection portion is formed on the outer shell 30 , and the outer shell 30 is not connected to the housing 210 .

[0126] Specifically, the housing 30 is not connected to the shell 210, so that the electrolyte level in the housing 30 is higher and the infiltration path is shorter, and there may be multiple winding cores 100 in the housing 30 (see Fig.10 ), each winding core 100 is provided with a cushion 20, and the housing 210 may have a plurality of winding cores 100 or one or more winding cores 100. Fig.10 In the embodiment of the group of cores 100 shown, in which a plurality of cores 100 are included in a shell 30 , preferably a buffer pad 20 is provided on the inner ring 101 of each core 100 , or at least one core 100 is provided with a buffer pad 20 , and the above-mentioned buffer pads 20 may also be provided between adjacent cores 100 .

[0127] It should be pointed out that a liquid injection portion may be formed on the top plate of the housing 30 , and the top plate and the bottom guard plate 32 are disposed opposite to each other in the winding axial direction.

[0128] Thus, the usage scenarios of the winding core 100 can be enriched, making the battery cells 200 of the embodiment of the utility model more diverse.

[0129] The battery pack 300 according to the embodiment of the present invention includes: the battery cell 200 in the above embodiment.

[0130] The energy storage system according to the embodiment of the present utility model includes: the battery pack 300 in the above embodiment.

[0131] The electric device 400 according to the embodiment of the present invention comprises: the battery pack 300 in the above embodiment.

[0132] According to the winding core 100 of the embodiment of the utility model, the winding core 100 includes a core body 10, a buffer pad 20 and an outer shell 30. The buffer pad 20 is arranged on the winding center a. The outer shell 30 includes an insulating sheet 31 and a bottom guard plate 32. The insulating sheet 31 and the bottom guard plate 32 define a closed accommodating space b. One or more winding cores 100 are arranged in the accommodating space b. A buffer pad 20 is arranged in the inner ring 101 of the core of at least one winding core 100 to separate the outer shell 30 from the shell 210, and the gap in the outer shell 30 is smaller, thereby increasing the electrolyte liquid level, making the electrolyte reflux more timely, and the infiltration efficiency higher, which can inhibit the increase of polarization, and effectively buffer and protect the inner ring pole piece, optimize the inner ring curvature, reduce the inner end risk, and improve the cycle life.

[0133] Other structures and operations of the winding core 100, the battery cell 200, the battery pack 300, the energy storage system and the electrical device 400 according to the embodiment of the utility model are known to ordinary technicians in the field and will not be repeated here.

[0134] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0135] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A battery cell, characterized in that: include: A winding core and a shell, wherein the winding core is arranged in the shell, and the winding core comprises: A core (10), the core (10) being wound around a winding center (a), and having a center hole at the winding center; A buffer pad (20), wherein the buffer pad (20) is arranged in the central hole; The outer shell (30) defines a containing space (b), and the core (10) and the buffer pad (20) are both arranged in the containing space (b).

2. The battery cell according to claim 1, characterized in that: At least one of the two ends of the buffer pad (20) in the winding axial direction protrudes from the end of the core body (10) in the winding axial direction.

3. The battery cell according to claim 2, characterized in that: The core (10) comprises: a diaphragm (13) and a first pole piece and a second pole piece located on both sides of the diaphragm (13) in a winding radial direction, the buffer pad (20) protrudes from the first pole piece and the second pole piece, and the winding radial direction is orthogonal to the winding axial direction.

4. The battery cell according to any one of claims 1 to 3, characterized in that: The shell (30) comprises: an insulating sheet (31) located on the side of the core (10) and a bottom guard plate (32) located at one end of the core (10), and an end of the buffer pad (20) is closer to the bottom guard plate (32) than an end of the core (10).

5. The battery cell according to claim 4, characterized in that: The bottom guard plate (32) and the buffer pad (20) are integrally formed.

6. The battery cell according to claim 4, characterized in that: The bottom guard plate (32) is sealedly connected to the insulating sheet (31) so that the bottom of the accommodating space (b) is separated from the outside.

7. The battery cell according to claim 1, characterized in that: The buffer pad (20) comprises: a main body (21) and a protective layer (22), wherein the protective layer (22) covers the main body (21) to isolate the electrolyte.

8. The battery cell according to claim 7, characterized in that: The dimension of the main body (21) in the winding radial direction is 0.5 mm to 3 mm.

9. The battery cell according to claim 8, characterized in that: The size of the protective layer (22) in the winding radial direction is 10um to 50um.

10. The battery cell according to claim 7 or 8, characterized in that: The buffer pad (20) further comprises a connecting layer (23), wherein the connecting layer (23) is coated on the protective layer (22) and is suitable for being connected to the core (10).

11. The battery cell according to claim 1, characterized in that: There is at least one winding core, a liquid injection portion is formed on the outer shell (30), and the outer shell (30) is not in communication with the housing (210).

12. A battery pack, characterized in that: include: The battery cell according to any one of claims 1 to 11.

13. An energy storage system, characterized in that: include: The battery pack according to claim 12.

14. An electrical device, characterized in that: include: The battery pack according to claim 12.

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